You are 24 years old. It is safe to presume that you don't have any children. One reason for passing gas through vagina (along with fart) is because of an abnormal opening between vagina and rectum. This is generally due to injury to vagina during childbirth. Another reason is infection of vagina due to gas forming bacteria. The patient will have vaginal discharge along with gas. But it doesn't come out intermittently. It can also be due to weakness of the muscles which controls opening of anus and rectum. Patient can't distinguish between gas passing through rectum or vagina. You should visit a Gynaecologist in your area who can examine you and find a cause.

Nothing to worry it happens sometimes